Cardboard box



Jan. 30, 1968 K. R. PERSSON CARDBOARD BOX Filed Sept... 2'7, 1966 4 Sheets-Sheet l INVENTOR; Kurd RuneFtRsson MM W Jan. 30, 1968 K. R. PERSSON CARDBOARD BOX 4 Sheets-Sheet 2 Filed Sept. 27, 1966 'INVENTOR. Kurd Rune Fkasson BY Ntnumx K. R. PERSSON CARDBOARD BOX Jan. 30, 1968 4 Sheets-Sheet 5 Filed Sept. 27, 1966 INVENTOR. Kcmi Rune Pcasson Jan. 30, 1968 sso v 3,366,307

CARDBOARD BOX Filed Sept. 27, 1966 4 Sheets-Sheet 4.

I N V EN TOR. Kcud Runc Peasson BYWMANQP Onthmmx United States Patent 3,366,307 CARDBOARD BOX Karl Rune Persson, Halmstad, Sweden, assignor to Sprinter-Pack AB, Halmstad, Sweden Filed Sept. 27, 1966, Ser. No. 582,372 Claims priority, application Sweden, Sept. 30, 1965, 12,696/ 65 3 Claims. (Cl. 22939) This invention relates to cardboard boxes in the form of parallelepipeds having two wide side walls, two narrow side walls and two opposite end walls, wherein one of the narrow side walls is formed by two overlapping wing flaps at the longitudinal edges of the wide side walls, whereas the end walls are formed by overlapping end flaps at the ends of the wide side walls, and wherein each end wall is locked due to the fact that the front edge of the overlying end flap is formed with a lock tongue inserted through a corresponding slot in the underlying end flap which has two slots parallel to the longitudinal edges of the end wall, one of said slots receiving the lock tongue of the overlaying end flap and the other one being located right below an additional slot in the overlying end flap, which additional slot has a deviating portion along part of its length, said portion forming a second look tongue which extends in a direction opposite to the direction of the first-named lock tongue and is flexed down into the slot of the underlying end flap for holding the slot edges located on either side of the lock tongue in a position in which they cross the opposing edge of the underlying slot and about said edge, whereby to lock the overlying end flap.

In order to erect the box, the end walls are formed and then the box is placed on one of the narrow side walls While the other narrow side wall is left open due to the fact that the wing flaps at that opening are in upright positions. In this position the box is filled and is then closed by turning the wing flaps downward and glueing or heat sealing said flaps.

The general object of the invention is to provide a box referred to above which is easy to open and also can conveniently be closed again.

To this end the box according to the invention is characterized by the features indicated in the annexed claims. Due to the fact that the opposite directed lock tongues are held in place by the two slots the tongues can be relatively short which is advantageous from the point of view of preventing the lock tongues from getting locked by freezing. The strip-like portion of the overlying end flap located between the lock tongues can therefore very easily be torn off along the fold lines and slots according to the invention for opening the box. Thereafter renewed closing is possible by means of the remaining portion of the overlying flap and the side tabs at the ends of the underlying flap.

These and other details and advantages of the invention are explained more closely in the following description of an exemplified embodiment of the box according to the invention illustrated in the annexed drawings.

FIG. 1 illustrates the blank for making the box according to the invention. FIG. 2 illustrates the box in upright position for filling. FIG. 3 is a diagrammatic perspective view of one of the end walls of the box. FIG. 4 is a perspective view of the other end wall of the box provided with projecting tabs which facilitate tearing for opening this end wall. FIG. 5 is a cross-sectional View along the line 55 in FIG. 3 and illustrates how the two oppositedly directed lock tongues are held in place each by a slot in the underlying end flap. FIG. 6 is a perspective view of the end wall shown in FIG. 4 after tearing and opening, and FIG. 7 is a perspective view of the end wall in FIG. 6 after renewed closing.

3,366,307 Patented Jan. 30, 1968 The blank shown in FIG. 1 is by longitudinal and transverse fold lines subdivided into two wide side walls 10, 11 and a narrow side wall 12 between the wide side walls. Wing flaps 13, 14 at the longitudinal edges of the wide side walls are intended to form the other narrow side wall of the erected box.

Articulated to the ends of the wide side wall 10 are end flaps 15, 16 having each two parallel slots 17, 18. Articulated to the ends of the other wide side wall 11 are end flaps 19, 20 having each a lock tongue 21 at the front edge and a slot 22 which along part of its length has a deviating portion 23 forming a small lock tongue 24 which extends in a direction opposite to the direction of the lock tongue 21.

The end flap 20 also has weakening lines and slots 25 located in line with the slot 22. The weakening slots have obliquely laterally directed portions which facilitate tearing off of the end flap in a manner described below. Provided at the ends of the end flap 20 are two freely projecting tabs 26 which facilitate the tearing operation. The other end flap 19, too, may be provided with weakening lines and tear-off tabs for facilitating tearing in the manner described above.

The end of the end flaps 15, 16 have extensions in the form of side tabs 27, 28 which have a rounded edge 29 on one side.

To erect the box into the position shown in FIG. 2 the wide side walls 10, 11 are folded relative to the intermediate narrow side wall 12 into upright positions and at the same time the lower side tabs 27 are moved inwards over the narrow side wall 12.

The end flaps 19, 20 provided with the lock tongues form the overlying end flaps at the end walls. The lock tongues 21 are inserted through the slots 18 and the final locking is effected by subjecting the triangular lock tongu1es'24 to external pressure so that they will snap down through the slot 17 to the locked position shown in FIG. 5. It will be seen that in this position the lock tongue 24 extends down below one edge of the slot 17 in the underlying end flap. At the same time the slot edges on either side of the lock tongue 24, i.e., the edges which merge into the edges that define the lateral edges of the lock tongue, will cross the slot edge lying above the lock tongue. Therefore, locking can be considered accomplished due to the fact that two slot edges are crossing each other at two places and are directly abutting each other resulting in that the interlocked parts can resist comparatively great pulling forces without getting unlocked. Consequently, the lock tongue 24 will not take the major part of the pulling forces which will act on the slot edges crossing each other.

In spite of the relatively short length of the two lock tongues as will be apparent from the drawings the box will be reliably closed.

After the box shown in FIG. 2 has been filled the two wing flaps are folded one above the other and secured to each other by a suitable adhesive.

The box is opened by grasping one or the other tab 26 and tearing off the strip-like portion of the overlying flap 20 between the outer lock tongue 21 and the inner lock tongue 24. Tearing takes place along the slot 22 and the slots 25, and the two lock tongues 21, 24 will be readily withdrawn from their slots.

If the box is to be closed again from the condition shown in FIG. 6 the remaining portion 20a of the end fiap is first turned inward whereupon the side tabs 27, 28 of the other end flap 15 are guided down along the insides of the narrow side walls 12, 13, 14 in order to keep the end flap 15 in the downwardly folded closed position according to FIG. 7 by frictional engagement with the insides of the narrow side walls and with the edges of the remaining portion 28a of the end flap 20.

3 What I claim is:

1. A cardboard box in the form of a parallelepiped having two wide side walls, two narrow side walls and two opposite end walls, wherein one of the narrow side walls is formed by two overlapping wing flaps at the longitudinal edges of the Wide side walls, whereas the end walls are formed by overlapping end flaps at the ends of the wide side walls, and wherein each end wall is locked due to the fact that the front edge of the overlying end flap is formed with a lock tongue inserted through a corresponding slot in the underlying end flap which has two slots parallel to the longitudinal edges of the end wall, one of said slots receiving the lock tongue of the overlying end flap and the other one being located right below an additional slot in the overlying end flap, which additional slot has a deviating portion along part of its length, said portion forming a second lock tongue which extends in a direction opposite to the direction of the first-named lock tongue and is flexed down into the slot of the underlying end flap for holding the slot edges located on either side of the lock tongue in a position in which they cross the opposing edge of the underlying slot and abut said edge, whereby to lock the overlying end flap, characterized in that the overlying end flap has means defining an easily tearable portion between the two lock flaps, and that the ends of the underlying end flaps are extended by side tabs which after said tearable portion has been torn off are intended to be used for renewed closing of the end wall by the steps of turning the remaining portion of the preexistent overlying end flap inwards and thereupon turning the formally underlying end flap downwards and simultaneously guiding the side tabs down along the insides of the narrow side walls.

2. A cardboard box as claimed in claim 1 in which at least one end of the tearable portion of the overlying flap is formed with a freely projecting tear-0E tab.

3. A cardboard box as claimed in claim 1, characterized in that the wing flaps of the wide side walls are adhesively connected to each other.

References Cited UNITED STATES PATENTS 3,104,795 9/1963 Adams 229-39 FOREIGN PATENTS 1,355,681 2/1964 France.

DONALD F. NORTON, Primary Examiner. 

1. A CARDBOARD BOX IN THE FORM OF A PARALLELEPIPED HAVING TWO WIDE SIDE WALLS, TWO NARROW SIDE WALLS AND TWO OPPOSITE END WALLS, WHEREIN ONE OF THE NARROW SIDE WALLS IS FORMED BY TWO OVERLAPPING WING FLAPS AT THE LONGITUDINAL EDGES OF THE WIDE SIDE WALLS, WHEREAS THE END WALLS ARE FORMED BY OVERLAPPING END FLAPS AT THE ENDS OF THE WIDE SIDE WALLS, AND WHEREIN EACH END WALL IS LOCKED DUE TO THE FACT THAT THE FRONT EDGE OF THE OVERLYING END FLAP IS FORMED WITH A LOCK TONGUE INSERTED THROUGH A CORRESPONDING SLOT IN THE UNDERLYING END FLAP WHICH HAS TWO SLOTS PARALLEL TO THE LONGITUDINAL EDGES OF THE END WALL, ONE OF SAID SLOTS RECEIVING THE LOCK TONGUE OF THE OVERLYING END FLAP AND THE OTHER ONE BEING LOCATED RIGHT BELOW AN ADDITIONAL SLOT IN THE OVERLYING END FLAP, WHICH ADDITIONAL SLOT HAS A DEVIATING PORTION ALONG PART OF ITS LENGTH, SAID PORTION FORMING A SECOND LOCK TONGUE WHICH EXTENDS IN A DIRECTION OPPOSITE TO THE DIRECTION OF THE FIRST-NAMED LOCK TONGUE AND IS FLEXED DOWN INTO THE SLOT OF THE UNDERLYING END FLAP FOR HOLDING THE SLOT EDGES LOCATED ON EITHER SIDE OF THE LOCK TONGUE IN A POSITION IN WHICH THEY CROSS THE OPPOSING EDGE OF THE UNDERLYING SLOT AND ABUT SAID EDGE, WHEREBY TO LOCK THE OVERLYING END FLAP, CHARACTERIZED IN THAT THE OVERLYING END FLAP HAS MEANS DEFINING AN EASILY TEARABLE PORTION BETWEEN THE TWO LOCK FLAPS, AND THAT THE ENDS OF THE UNDERLYING END FLAPS ARE EXTENDED BY SIDE TABS WHICH AFTER SAID TEARABLE PORTION HAS BEEN TORN OFF ARE INTENDED TO BE USED FOR RENEWED CLOSING OF THE END WALL BY THE STEPS OF TURNING THE REMAINING PORTION OF THE PREEXISTENT OVERLYING END FLAP INWARDS AND THEREUPON TURNING THE FORMALLY UNDERLYING END FLAP DOWNWARDS AND SIMULTANEOUSLY GUIDING THE SIDE TABS DOWN ALONG THE INSIDES OF THE NARROW SIDE WALLS. 